Inhibition of thromboxane synthase activity modulates bladder cancer cell responses to chemotherapeutic agents.

Recently, we reported prognostic significance of thromboxane synthase (TXAS) gene expression in invasive bladder cancer. The positive correlation between elevated TXAS expression and shorter patient survival supports a potential role for TXAS-regulated pathways in tumor metastases. In this study, using immunohistochemical analysis, we found an increased expression of TXAS protein in bladder cancer. Treatment of T24 and transitional cell carcinoma TCC-SUP bladder cancer cells with the TXAS inhibitors furegrelate or ozagrel induced an apoptotic effect measured as an increase in caspase-3 activation and cell death, and decreased survivin expression. Pharmacological inhibition of TXAS using the TXAS inhibitor furegrelate increased sensitivity to the chemotherapeutic agents cisplatin and paclitaxel. Molecular inhibition of TXAS expression by siRNA significantly decreased cell growth and migration. In concordance with the pharmacological data, siRNA-mediated reduction of TXAS expression increased sensitivity to cisplatin and paclitaxel in T24 and TCC-SUP cells. In summary, the data support a role for the thromboxane A(2) pathway in the pathogenesis of bladder cancer and the potential utility of modulation of this signaling pathway for cancer chemotherapy.

Is endosonography guided fine needle aspiration (EUS-FNA) for sarcoidosis as good as we think?

BACKGROUND: Preliminary data show that endosonography guided fine needle aspiration (EUS-FNA) may be an accurate method for diagnosing sarcoidosis. However, these data were obtained in a small selected group of patients with a very high pretest probability of sarcoidosis. This retrospective study reports on the use of EUS-FNA in an unselected group of patients with mediastinal lymphadenopathy of unknown origin. METHODS: The EUS database of a single tertiary referral centre was reviewed for patients who underwent EUS-FNA for mediastinal lymphadenopathy of unknown origin. Clinical presentation and imaging studies of each case were carefully reviewed and the diagnosis "sarcoidosis" or "no sarcoidosis" attributed if possible. The diagnoses were compared with the result of EUS-FNA. RESULTS: One hundred and twenty four patients were investigated. In 35 cases EUS-FNA identified granulomas (group 1); in the other 89 cases (group 2) no granulomas were detected. The definite diagnoses in group 1 were sarcoidosis (n = 25), indefinite (n = 7), no sarcoidosis (n = 3). The definite diagnoses in group 2 were sarcoidosis (n = 3), indefinite (n = 9), no sarcoidosis (n = 77). Of the 77 cases with no sarcoidosis, 44 were diagnosed with other diseases. The other 33 showed non-specific changes in the FNA and sarcoidosis was excluded by negative non-EUS pathology (n = 17) and clinical presentation. The sensitivity and specificity for EUS-FNA were 89% (95% CI 82 to 94) and 96% (95% CI 91 to 98), respectively, after exclusion of the indefinite cases in both groups. CONCLUSIONS: EUS-FNA is an accurate method for diagnosing sarcoidosis in an unselected group of patients with mediastinal lymphadenopathy. The reported sensitivity and specificity must be appreciated in the context of the difficult and often incomplete clinical diagnosis of sarcoidosis.

Comparison of EUS-guided 19-gauge Trucut needle biopsy with EUS-guided fine-needle aspiration.

BACKGROUND AND STUDY AIMS: The accuracy of endoscopic ultrasound-guided fine-needle aspiration (EUS-FNA) depends on immediate specimen review by a cytopathologist. Stromal tumors, lymphoma, and well-differentiated pancreatic cancer are difficult to diagnose on the basis of cytology alone. To overcome these limitations, a 19-gauge Trucut needle has been developed to obtain histological samples at EUS. This pilot study compares the specimen adequacy and diagnostic accuracy of EUS-guided Trucut needle biopsy (EUS-TNB) with EUS-FNA. PATIENTS AND METHODS: A total of 18 patients underwent EUS-TNB and EUS-FNA. The specimen adequacy and diagnostic accuracy of the two techniques was compared. The technical performance and safety profile of the Trucut needle were also evaluated. RESULTS: The EUS-TNB specimen was adequate for evaluation in 15/18 patients compared with 18/18 with EUS-FNA (83 % vs. 100 %, not significant). The diagnostic accuracy of EUS-TNB was not significantly different from EUS-FNA (78 % vs. 89 %). Two complications were encountered: one patient developed mediastinitis and required surgery; another had immediate bleeding that was managed conservatively. One technical problem was encountered: the Trucut needle failed to deploy after two passes when a gastric stromal cell tumor was being biopsied. CONCLUSION: The diagnostic accuracy of the new EUS-TNB is comparable to that of EUS-FNA. In our experience, the overall efficacy and safety profile of the Trucut needle appears modest.

Defects of DNA mismatch repair in human prostate cancer.

Loss of mismatch repair (MMR) function leads to the accumulation of errors that normally occur during DNA replication, resulting in genetic instability. Germ-line mutations of MMR genes in the patients with hereditary nonpolyposis colorectal cancer lead to inactivation of MMR protein functions, and the defects of MMR are well correlated to the high rate of microsatellite instability in their tumors. Previous studies (T. Uchida, et al. Oncogene, 10: 1019-1022, 1995; S. Egawa, et al. Cancer RES:, 55: 2418-2421, 1995; J. M. Cunningham, et al. Cancer RES:, 56: 4475-4482, 1996; X. Gao, et al. Oncogene, 9: 2999-3003, 1994; H. Rohrbach, et al. Prostate, 40: 20-27, 1999) have shown that genetic instability (chromosomal and microsatellite instability) is detectable in human prostate cancer. To elucidate the role of MMR genes in the tumorigenesis of prostate cancer, we evaluated the expression of these genes in human cancer cell lines and in tumor specimens. Using Western blot analysis, we detected loss among MSH2, MLH1, PMS2, and PMS1 proteins in DU145, LNCaP, p69SV40T, M2182, and M12 cells. In addition, genomic instability in the prostate cell lines including DU145, PC3, LNCaP, p67SV40T, M2182, and M12 was detected by a microsatellite mutation assay. Significantly, immunohistochemical analysis of prostatic tissue revealed the reduction or absence of MMR protein expression in the epithelium of prostate tumor foci compared with normal adjacent prostate tissue. In contrast to hereditary nonpolyposis colorectal cancer, characterized by defects predominantly in MLH1 and MSH2, the samples we examined showed more tumor foci with loss of PMS1 and PMS2. PMS1, which is only expressed in the basal cells in normal glands, is conspicuously absent in most prostate cancer. From these results, we conclude that there are defects of MMR genes in human prostate cancer.

Interaction of human immunodeficiency virus type 1, human T-cell leukemia/lymphoma virus type I (HTLV-I), and HTLV-II with in vitro-generated dendritic cells.

Although it is known that impairment of dendritic cells (DC) plays a role in the pathogenesis and immunosuppression of retrovirus-associated diseases, it is not clear whether, or to what extent, these antigen-presenting cells themselves become infected. The realization that the cells can be generated in vitro in larger numbers than can be isolated from circulating blood or bone marrow raised the possibility that they could be used for therapeutic purposes. Therefore, we investigated whether DC generated in vitro from CD34 precursors are susceptible to infection when cocultured with human immunodeficiency virus type 1- or human T-cell leukemia/lymphoma virus-infected cell lines. While there appears to be a remarkable affinity of the viruses for the plasma membranes of the DC, interiorization or budding was not observed in 30 experiments carried out under a variety of conditions.

Newer approaches in treating chronic myelogenous leukemia.

Allogeneic bone marrow transplantation (BMT) is a useful approach for treating patients with chronic myelogenous leukemia (CML). In patients who lack a suitable donor, various approaches to utilize the patient's own hematopoietic stem cells obtained from bone marrow and/or peripheral blood have been developed. Preferential recovery of normal human hematopoietic progenitors over CML clone in long-term bone marrow culture (LTBMC) has been observed for a long time. LTBMC initiated in tissue culture (TC) flasks to that in "Lifecell" bags, which are gas-permeable plastic bags in which feeder-layer cells cannot adhere, has been investigated for several years. In our laboratory, cells were incubated in the presence of various growth factors to develop improved methods for stem cell expansion. Sustained hematopoietic stem cell growth in the absence of a feeder layer in plastic gas-permeable bags has been observed. Growth of marrow from patients with CML is being investigated extensively. Combining effective drugs to decrease the Philadelphia (Ph) clone prior to bone marrow harvest and the use of cultured bone marrow may provide a useful method for treating patients with CML. Results of various international studies are also discussed below.

Purging in autologous and allogeneic bone marrow transplantation.

The success of hematoablative dosages of cytotoxic therapy followed by stem cell transplantation depends on the disease response to the intensive drug dose and the ability of the transplant to provide durable hematopoietic reconstitution. In autologous stem cell transplantation, patients' own bone marrow or peripheral blood is used for hematopoietic engraftment. In several diseases the bone marrow is involved, and in such situations, the success of autologous stem cell transplantation may improve if the hematopoietic elements are enriched (positive selection) or if the contaminating cancer cells are purged by negative selection. In patients undergoing allogeneic bone marrow transplantation, the T lymphocytes of the donor cells contribute to the development of graft-versus-host disease with significant morbidity and mortality. Selective purging of T lymphocytes has dramatically decreased the incidence of graft-versus-host disease. In this paper, various methods for purging hematopoietic stem cells are detailed with emphasis on treatment planning. Exciting new possibilities include growing stem cells from a small amount of bone marrow, enhancing immune surveillance, and decreasing drug resistance by genetic engineering.